Method for detecting a rotation angle position of moveable cylinder of a printing machine

ABSTRACT

The rotation angle position of a moveable component, such as a cylinder, is detected or determined through a method in which the detected rotation angle position is modified using a correction value when the moveable component is in a second position.

FIELD OF THE INVENTION

The present invention relates to a method for determining an angle ofrotation position of a movable cylinder of a printing press.

DESCRIPTION OF THE PRIOR ART

A device for an angular position sensor is known from DE 196 14 818 A1,wherein a stator of the angular position sensor is arranged at a fixedangle in respect to the lateral frame.

DE 197 20 952 A1 describes a method for compensating a rotating movementsuperimposed on the rotating movement of a cylinder because of aneccentric movement. The compensation is performed by a control circuit,which is supplied with the actual angle of rotation of the cylinder inrespect to an eccentric device, as well as with the actual angle ofrotation of the eccentric device, or with an angular function derivedtherefrom.

SUMMARY OF THE INVENTION

The object of the present invention is directed to providing a methodfor determining an angle of rotation of a movable cylinder of a printingpress.

In accordance with the invention, this object is attained by using anangle of rotation position sensor. A first angle of rotation of thecomponent in a reference position is determined. In a second position ofthe component, a second angle of rotation is also determined. Adifference between the two is used as the correction value fordetermining the actual angular position of the component in its secondposition.

In connection with the drive mechanism in accordance with the presentinvention for cylinders of a printing press, it is possible in anadvantageous manner to arrange an angle of rotation position sensor inany arbitrary manner, i.e. an angle of rotation position of the angle ofrotation position sensor in respect to the lateral frame need not beconstant during the movement of the cylinder.

It is also possible to remove errors, for example as a result ofproduction-related tolerances.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is represented in thedrawings and will be described in greater detail in what follows.

Shown are in:

FIG. 1, a schematic representation of a longitudinal section through abearing of a cylinder,

FIG. 2, a schematic representation of the lateral view in accordancewith FIG. 1, and in

FIG. 3, a schematic representation of a block wiring diagram of a drivecontrol.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 represents a longitudinal section of a rotating component of aprinting press, for example a cylinder 1, which is rotatably drivenaround its longitudinal axis, called the axis of rotation 2 of thecylinder in what follows, and which is pivotable around a pivot axis 5.The cylinder 1 is rotatably seated in an eccentric bushing 3 by abearing 4 on its two outer cylinder journals, only one of which outercylinder journals is represented in FIG. 1. The eccentric bushing 3itself is rotatably seated in a sliding bearing in a machine frame 6.The cylinder 1 is pivoted in a generally known manner about the pivotaxis 5 by operation of the eccentric bushing 3. The pivot axis 5 is alsothe axis of rotation of the eccentric bushing 3 in the machine frame 6.The distance between the axis of rotation 2 of the cylinder and thepivot axis 5 is the eccentricity e.

An angle of rotation position sensor 9 has been fastened, in a mannerfixed against relative rotation in respect to the axis of rotation 2 ofthe cylinder, on the outermost journal end of the cylinder 1 as seen inFIG. 1. The angle of rotation position sensor 9 is comprised of an innerring 10 and a circular first measuring disk 13, which is rigidlyconnected with it. The application, of the inner ring 10 on the journalof the cylinder 1 in a manner fixed against rotation, is indicated by acotter pin 11. The first measuring disk 13 has a known circulargraduation with a multitude of lines extending in the radial direction.An outer ring 14, which is slidingly rotatably seated on the inner ring10, and with which a second circular disk 15 is rigidly connected,encloses the inner ring 10. This second or scanning disk 15 is providedwith a multitude of photo elements for scanning the line graduation ofthe first or measuring disk 13. The relative angle of rotation positionof the first or measuring disk 13 with respect to the second or scanningdisk 15, which is therefore used as a reference (relation) for the angleof rotation position of the first measuring disk 13, is determined bymeans of photo-electrical scanning, which photo-electric scanning merelyrepresents a preferred embodiment of the scanning process, but to whichthe invention is not exclusively limited, and by the angle of rotationposition of the cylinder 1 in respect to the outer ring 14, which isused as the reference element 14 and which has the second or scanningdisk 15, called reference disk 15 in what follows. The outer ring 14 andthe reference disk 15 constitute a reference element for the angularposition sensor 9.

A support arm 30 is seated, pivotable around a pivot axis 31, on themachine frame 6. On its end remote from the pivot axis 31, the supportarm 30 has an elongated recess 32, which, as seen in FIG. 2 is embodiedas a simple elongated hole in the preferred embodiment. The pivot axis31 of the support arm 30 extends parallel with the axis of rotation 2 ofthe cylinder. A rigid guide element 17, which is rigidly connected withthe reference element 14, is force-guided in the course of a pivotmovement of the cylinder 1. The reference element 14 is maintained inits zero position during a printing operation by means of the forcedguidance, in particular during pivoting of the axis of rotation 2 of thecylinder.

The arrangement in accordance with FIG. 1 is represented in FIG. 2 in afront view on the cylinder 1. By operation of a motor M or a workingcylinder, which acts on the eccentric bushing 3, the cylinder 1 ispivoted around the pivot axis 5, which simultaneously represents thepivot axis of the cylinder 1, by an angle α from its zero position,namely the printing position. In the course of this pivot movement, theaxis of rotation 2 of the cylinder describes an arc s of a segment of acircle and moves into the pivoted-away position indicated by 2′, as seenin FIG. 2.

In the preferred embodiment in accordance with FIGS. 1 and 2, thereference element 14 is rigidly connected with the guide element 17,which is force-guided at a close lateral distance in the recess 32 ofthe support arm 30. In the preferred embodiment the guide element 17 isdesigned as a simple square bolt, which is guided, sliding in the recess32, in a purely translatory manner; tilting is prevented by this. In thecourse of pivoting the cylinder 1, the angle of rotation position of thecylinder 1 does not change by the amount of the pivot angle α of thecylinder 1, but by the amount of the smaller pivot angle β of thesupport arm 30.

Thus, the cylinder 1 can be pivoted out of a first operating position,for example “print ON”, into a second operating position “print OFF”. Ifthe cylinder 1 is arranged to be not rotatable, for example in relationto the eccentric bushing 3, the rotor 13 and the stator 15 of the angleof rotation position sensor 9 rotate in respect to each other.

A second actual value β 2, which is in relation to the second operatingposition, is determined. A correction value is fixed from a differencebetween the actual value β 1, determined in a first operating position,and the actual value β 2. If the cylinder is now driven in the secondoperating position, a computer 33 is supplied with the previouslydetermined correction value and corrects the actually determined actualvalue by this correction value during the operation of the cylinder inits second operating position. This means that the actual value of therotating component 1, as well as the correction value are determined bya single angle of rotation position sensor 9.

This correction value can also be calculated from the geometricrelationships and can be determined without a measurement by means of anangle of rotation sensor.

Thus, a pre-calculated correction value is supplied to the computer 33as a “manually” determined constant value.

It is also possible to fix a plurality of correction values for theentire course between the first and second operating positions. For thispurpose, it would be possible, for example, to determine correctionvalues as a function of the chronological course of the position changesof the cylinder 1, i.e. a function of correction values depending on thetime.

It is also possible to assign a position sensor to the cylinder 1 whichdetermines a position of the eccentric bushing 3, and therefore aposition of the axis of rotation of the cylinder in respect to themachine frame 6. By means of this, it is possible to determinecorrection values as a function of the position of the cylinder 1.

It is also possible to determine the correction values as a function oftime, or of the position, either in discrete steps or continuously.

The position of the cylinder is understood to mean the position of theaxis of rotation 2 of the cylinder 1 in relation to the machine frame 6.

An output element 34 is connected downstream of the computer 33 forcontrolling a drive motor 36 for driving the cylinder 1.

While a preferred embodiment of a method for detecting a rotation angleposition of a moveable cylinder of a printing machine in accordance withthe present invention has been set forth fully and completelyhereinabove, it will be apparent to one of skill in the art that anumber of changes in, for example, the overall size of the cylinder, thedrive for the cylinder and the like could be made without departing fromthe true spirit and scope of the present invention which is accordinglyto be limited only by the following claims.

What is claimed is:
 1. A method for determining an angle of rotationportion of a moveable rotating component of a printing press including:providing an angle of rotation position sensor; using said angle ofrotation position sensor and determining a first angle of rotationposition of the rotating component in a first, reference position of thecomponent; using said angle of rotation position sensor and determininga second angle of rotation position of the rotating component in asecond position of the component; determining a difference between saidfirst angle of rotation position and said second angle of rotationposition; using said difference as a correction value; and determiningan actual angular position of the rotating component in said secondposition using said correction value.
 2. The method of claim 1 furtherincluding using said angle of rotation position sensor for determiningsaid correction value.
 3. The method of claim 1 further includingdetermining said correction value using geometric relationships.
 4. Themethod of claim 1 further including determining a plurality of saidcorrection values.
 5. The method of claim 1 further includingdetermining said correction value as a function of chronologicalprogress in the change of position of said rotating component.
 6. Themethod of claim 1 further including assigning a position sensor to therotating component and determining said correction value as a functionof a position of the rotating component.
 7. The method of claim 1wherein the rotating component is a roller.
 8. The method of claim 1wherein the rotating component is a cylinder.
 9. The method of claim 1further including movably seating the rotating component in eccentricbushings.